We propose to evaluate the quality and extent of safety information in published randomized trials across several medical disciplines and to identify factors that affect the reporting of safety data in these reports. Such trials offer a unique opportunity for assembling information on the toxicity profile of new interventions in a controlled, comprehensive setting. This information cannot be substituted from small, selective early phase I/II trials or the sporadic post-marketing experience. The evaluation of safety reporting from randomized trials is a neglected field. However, clinicians cannot make informed risk-benefit decisions without adequate information on the toxicity of specific medical interventions beyond efficacy estimates. We have developed scales for evaluating safety reporting in randomized trials and have applied them to all trials in the field of HIV therapeutics. Glaring deficiencies were observed in the reporting of discontinuations due to toxicity and the reporting of specific side effects. The journal space allocated to safety results was slightly less than that allocated for contributor names. In this project, we will assess the qualitative and quantitative adequacy of safety reporting in comprehensive databases of randomized comparative trials in 7 different clinical fields; HIV infection, thrombolytic therapy in acute myocardial infarction, treatment of hypertension in the elderly, antibiotic therapy for acute sinusitis, non-steroidal agents for rheumatoid arthritis, treatment for Helicobacter pylori, and selective decontamination of the gastrointestinal tract in the intensive care setting. A meta-analysis of the estimates of safety reporting across these fields will be used to assess field-specific heterogeneity and to calculate overall pooled estimates, if appropriate. The project is expected to detect deficiencies in current reporting of safety data and show how the situation can be improved in the future, thus promoting the potential for the application of evidence-based medicine in clinical practice.